Recently, .beta.-silicon carbide has been widely used as filler and binder for refractory, deoxidizer in metallurgy, abrasive for polishing, pigment for high-temperature use and raw material for sintering due to its excellent chemical and physical properties over .alpha.-silicon carbide.
A method of producing .beta.-silicon carbide is lately disclosed in Japanese Patent Laid Open Application No. 160,200/75 entitled as "Silicon carbide powder for sintering and a method of producing the same". In this method, .beta.-silicon carbide is produced by a gaseous phase reaction by means of a particular apparatus. However, raw materials adapted to be used in the gaseous phase reaction are relatively expensive and easily hydrolyzed in air, and the yield of .beta.-silicon carbide in the gaseous phase reaction is generally low, and hence the products are always expensive, and the production of .beta.-silicon carbide by the gaseous phase reaction is disadvantageous.
Further, a method of producing .beta.-silicon carbide inexpensively in a large scale is disclosed in Japanese Patent Laid Open Application No. 142,697/77 entitled as "Continuous method of producing .beta.-silicon carbide". In this method, since raw material silica consisting of relatively large particles having an average particle size of 3-10 mm is used, the reaction rate is very low at a temperature of not higher than 1,650.degree. C., and therefore a very high temperature of higher than the melting point (about 1,710.degree. C.) of silica is required in the commercial production of .beta.-silicon carbide. Moreover, in order to prevent sticking of raw material mixture by silicon monoxide formed during the reaction, unreacted silica and carbon must be intentionally left in the reaction product, and therefore the yield of .beta.-silicon carbide is low and a superfluous operation must be carried out in order to remove these unreacted silica and carbon.
The present invention aims to obviate these drawbacks. That is, in the present invention, silica having a particle size of not larger than 150 .mu.m is used in order to complete a major part of reaction at a relatively low temperature of not higher than 1,650.degree. C., and further silicon monoxide formed during the reaction is prevented from escaping from the reaction system, and the captured silicon monoxide is again contacted with unreacted carbon at reaction temperature, whereby .beta.-silicon carbide is produced in a sufficiently high efficiency.